Treatment of hydrocarbon oil



Nov. 13, 1934. w, H. McADAMs E1- AL,

TREATMENT OF HYDROCARBON OIL FiledA April 19. 1932 Patented Nov. 13,1934 TREATMENT or nnmocAaBoN on.

William H. McAdams, Newton, and Harold IC. Weber, Milton, Mass.,assignors to Universal 0i1 Products Company, Chicago, Ill., acorporation of South Dakota Application April 19, 1932, Serial No.606,180

6 Claims.

'Ihis invention relates to the treatment of hydrocarbon oils, and moreparticularly refers to an improved process and apparatus for theconversion of relatively heavy oils or oils of inferior quality toproduce substantial yields of a desirable light product stabilized withrespect to its boiling point and vapor pressure.

The present invention provides an improved method and means of producinga stabilized distillate product direct from the cracking system and inits primary principles comprises an improved methodv and means ofstabilizing the distillate vapors within the cracking system prior totheir nal condensation, utilizing to best advantage heat stored withinsaid vapors and the operating pressure of the system to assist saidstabilization.

A special feature of the invention comprises the use of a portion of thegaseous conversion products such as propane, butane, pentane, etc., ascooling means within the upper portion of the stabilizer by cooling andcondensing a portion of said gaseous products, separating andwithdrawing the uncondensed fractions, and returning the condensate, atleast in part, to the top of the stabilizer.

Another feature of the invention comprises the use of relatively hotvaporous conversion products from the reaction zone of the crackingsystem as a means of reboiling distillate collected in the lower portionof the stabilizer and subsequently withdrawn therefrom as the stabilizeddistillate product of the process. This is accomplished by indirectcontact and heat exchange nents of the vapors, returning saidinsufciently converted materials as reflux condensate from thefractionator to the heating element for further conversion, subjectingvaporous products from the fractionator comprising materials ofsubstantially motor fuel boiling range and gases to furtherfractionation in a stabilizer preferably maintained at a substantialsuperatmospheric pressure, from the gases and vapors generated withinthe cracking system collecting, as condensate ,in the lower portion ofthe stabilizer, the motor fuel product of the system and reboiling thiscondensate to substantially free the motor fuel of gases anduncondensable lightA ends by indirect contact and heat exchange betweenthis material and vaporous products of the system passing from thereaction chamber to the fractionator,

cooling and collecting the stabilized motor fuely subjecting them tocooling and collection, there* after returning all or a portion of thecondensate to the upper portion of the stabilizer to serve as a coolingmeans to assist stabilization in this zone,

and withdrawing the uncondensed gases from theV system.

It will be understood that while the foregoing description has referredspecifically to the production of stabilized motor fuel the principlesof the invention are equally applicable to the production of any desiredcracked product in stabilized form.

The attached diagrammatic drawing illustrates one specific form ofapparatus embodying the principles of the present invention. Thefollowing description of the drawing includes the description of theprocess of the invention as it may be practiced in the apparatusillustrated.

Raw il charging stock for the system may be supplied through line 1 andvalve 2 to pump 3 from which it is fed through line 4 and may passthrough line 5, valve 6 and valve 7 into heating element 8. All, or anyportion of the raw oil may be preheated, if desired, prior to itsintroduction to the heating element, by any well known means, forexample, all or any portion of the raw oil may pass from line 4 throughline 9 and valve 10 into fractionator 11 wherein it is preheated bydirect contact with the relatively hot vapors in this zone, assistingtheir fractionation and passing together with their relatively heavycomponents, which are condensed in the fractionator, through line 12 andvalve 13 to pump 14. Pump 14 supplies the reflux condensate or refluxcondensate and preheatedl raw oil from fractionator 11 through line l5and valve 16 into line 5, and thence through valve 'I to heating element8.

Furnace 17 of any suitable form supplies to the oil passing throughheating element 8, the heat required for its conversion under thedesired pressure conditions employed in this zone. The heated oil passesfrom heating element 8 through line 18 and valve 19finto reactionchamber 20 which, like heating element 8, is preferably maintained at asubstantial superatmospheric pressure. The inlet and outlet connectionsto chamber 20 are preferably such that conversion, particularly of thevapors, may continue for a predetermined time in this zone while theliquid conversion produ cts are qujclgly separated from the vapors andmeans of maintaining this condition in chamber 20 may be employed, forexample, as illustrated in the drawing the heated materials from heatingelement 8 may enter the upper portion lof chamber 20, passingdownward-through this zone from the lower portion of which residual oilisremoved through line 21 and valve 22 while vaporous products passupward through the extended vapor line 13 to be withdrawn through line24 to fractiona- .Vapors from chamber 20 are withdrawn through line 24and valve 25 to fractionator 11, a portion thereof preferably passingthrough line 26, valve 26 and closed coil 28 in the lower portion ofstabilizer 27, for the purpose of reboiling the distillate f collectedin' the lower portion of this zone as will be later more fullydescribed, thence passing through line 30, valve 31 and line 24 tofractionation in fractionator 11.

Residual oil from chamber 20 withdrawn, as described, through line 21and valve 22 preferably passes to further vaporization in flashdistilling and valve 60. Vapors from chamber 29 may pass to separatefractionation, condensation, cooling and collection throughlines 32, 32and valve 33' (valve 33 being closed), condenser 69, line 70 and valve71 to vented receiver 61 and through line 64, valve Y65 and line 66 topump 3, a part of the distillate if desired, being drawn off throughline 68 and valve 67; or the vapors may pass through line 32, valve 33,pump or compressor 34, line 35 andvalve 36 to fractionatiominfractionator 11 together with material from chamber 20 introduced intothis zone, as already described.

Pump or compressor 34 need be employed only in case the pressure inchamber 29 does not exceed that in fractionator 11.

Vapors introduced into fractionator 11, as described, are separated byfractionation into relatively light components comprising vapors ofsubstantially motor fuel boiling range and gas and heavier componentswhich are condensed in the fractionator to be returned therefrom, asalready described, toheating element 8 for further conversion.

Vapors and gases from fractionator 11 pass through line 37 and valve 38to further fractionation or stabilization in stabilizer 27. Vapors ofsubstantially motor .fuel boiling range are condensed in this zone,collecting in the lower portion thereof, wherein they may be reboiledfor the purpose of substantially freeing them from vapors of excessivevolatility and uncondensable light ends by means of heat impartedthereto from the vapors passing through coil 28 as already described.The stabilized distillate product of the system is withdrawn from thelower portion of stabilizer 27 through line 39 and valve 40, passingthrough cooler 41 to storage or to any desired further treatment throughline 42 and valve 43.

Gaseous products and vapors are withdrawn from stabilizer 27 throughline 44 and valve 45 to be subjected to cooling and partial condensationin coil 46, thereafter passing through line 47 and valve 48 tocollection in receiver 49. This cooling andcollection is preferablyeffected under sub-V stantially the same pressure as that employed inthe stabilizer, and depending upon vthe degree of cooling employed incoil 46, a separate portion of the gaseous products being collected ascondensate in receiver 49.

'I'he cooled and uncondensed gases are released from receiver 49 throughline 50 and valve 51. A portion of the distillate collected in receiver49 may be released from the receiver through line 52 and valve 53, theremainder or all being withdrawn through line 54 and valve 55 to pump 56by means of which the condensate is returned through line 57 and valve58 to the upper portion of stabilizer 27, where itoserves as a means forcooling and assisting fractionation in the upper portion of thestabilizer. If desired, any well known means of cooling or refrigeratingin the upper portion of stabilizer 27 may be employed in conjunctionwith the method illustrated in the drawing. A part or all of the raw oilmaygif desired, be preheated to 700-800" F. and fed directly to flashchamber 29, instead of to fractionator 11 or coil 8 as shown in thedrawing. 'I'his alternative is desired when handling topped crudes.

superatmospheric pressures are employed within the system preferablyfrom several hundred pounds per square inch to as high as 1000 pounds ormore per square inch. Conversion temperatures employed may range from800 to 1100 F. The heating element is preferably maintained at vasubstantially superatmospheric pressure of the order of to 1000 poundsper square inch. Substantially the same range loi' pressures may beemployed in the reaction chamber while the fractionating, stabilizing,cooling and collecting portions of the system may be maintained atsubstantially the same or a somewhat lower pressure than that employedin the reaction chamber, substantial superatmospheric pressures of f theorder of 100 pounds or more, per square inch preferably being employedin the stabilizer. The residuum flash distilling chamber 29 ispreferably maintained'at a substantially reduced pressure relative tothat employed in the reaction chamber ranging, for example, fromsubstantial atmospheric to 100 pounds per square inch, or thereabouts. f

As a specific example of the operation of the process of the presentinvention, a 42 A. P. I. gravity Pennsylvania distillate is the chargingstock supplied to the system which is subjected, together with refluxcondensate from lthe system, to a temperature of approximately 910 F. at

the outlet from the heating element. A superatmospheric pressure ofapproximately 380 pounds per square inch is employed in the heatingelement and is substantially equalized in the reaction chamber. Thefractionating, stabilizing, cooling and collecting portions of thesystem are maintained at approximately 150 pounds per square inch.AStabilized distillate is withdrawn from the lower portion of thestabilizer at a temperature of approximately 310 F., and is subsequentlycooled to approximately atmospheric temperature. A temperature of about120 F. is maintained in the upper portion of the stabilizer. Residualoil from the reaction chamber is subjected to iiash distillation at areduced pressure of about 35 pounds per square inch, and the resultingvapors are subjected to condensation, the condensate being continuouslyrecharged to the system. This operation may result in the production ofa motor fuel product amounting to approximately 76% charging stockhaving an antiknock value approximately equivalentto a blend of 'I5-80%iso-octane and 25-20% normal heptane. 'Ihe motor fuel has an initialboiling point of approximately 100 F., an end boiling point ofapproximately 400 F., and is substantially free of iso-butane, propaneand lighter gases, but contains a suflicient amount of butane to give iteasy starting characteristics. The additional products Aof the systemmay comprise about 10% of residual oil based on the charging stock anda' rich noncondensable gas.

We claim as our invention:

1. .A process which comprises subjecting hydrocarbon oil to crackingconditions of temperature and pressure and separating the same intovapors and residue, dividing such separated vapors into two portions,introducing one of the portions into a fractionating zone andfractionating the same therein to condense fractions thereof heavierthan gasoline, passing the fractionated vapors to a stabilizing zone andcondensing and stabilizing the gasoline therein, the gasoline condensatebeing collected in the lwer portion of the stabilizing zone andwithdrawn therefrom as a product of the process, and passing the otherportion of the separatedl vapors, prior to any substantial cooling andcondensation thereof, in indirect heat exchange with the gasolinecondensate in the lower portion of the stabilizing zone.

2. A process which comprises subjecting hydrocarbon oil to crackingcondition of temperature and pressure and separating the same intovapors and residue, dividing such separated vapors into two portions,introducing one of the portions into a fractionating zone andfractionating the same therein to condense fractions thereof heavierthan gasoline, passing the fractionated vapors to a stabilizing zone andcondensing and stabilizing the gasoline therein, the gasoline condensatebeingv collected in the lower portion of the stabilizing zone andwithdrawn therefrom as a product of the process, and passing the otherportion of the separated vapors, prior to any substantial cooling andcondensation thereof, in indirect heat exchange with the.gasolinecondensate in the lower portion of the stabilizing zone and subsequentlyintroducing the same to the fractionating zone for fractionation andsubsequent stabilization in admixture with lthe rstmentioned por` tionof the vapors.

3. A process which comprises subjecting hydrocarbon oil to crackingtemperature in a cracking zone maintained under pressure thereby formingvapors and unvaporized oil, removing the vapors and unvaporized oil fromthe cracking zone and flash distillingthe latter by pressure reduction,passing the resultant flashed vapors and the vapors formed in thecracking zone to a fractionating zone` and fractionating the commingledvapors therein to condense fractions thereof heavier than gasoline,supplying the fractionated vapors to a stabilizing zone and condensingand stabilizing the gasoline therein thereby forming gasoline condensatein the lower portion of the stabilizing zone, and passing at least aportion of the first-mentioned vapors, while in transit from thecracking zone to the fractionating zone, in indirect heat exchange withthe gasoline condensate in the lower portion of the stabilizing zone.

4. In a process for the cracking of relatively higher boilinghydrocarbons into lower boiling hydrocarbons to produce a stabilizedmotor fuel, with respect to its vapor pressure, of the character whereinthe oil is heated to conversion conditions of temperature and pressurein a. heating coil, the products therefrom being discharged into areaction chamber, the improvement which comprises separating the vaporsand non-vaporous residue in the said reaction chamber, introducing thenon-vaporous residue into a zone of reduced pressure wherein a furtherseparation of vapors and non-vaporous residue occurs, removing thenon-vaporous residue from the system, compressing the `vapors leavingthe zone of reduced pressure and introducing the same into afractionator, removing the reflux condensate from the fractionator andreturning the same -to the heating coil for further conversion, removingthe vapors from the fractionator and introducing the same into astabilizer without substantial decrease in pressure, introducing intothe upper portion of the stabilizer a cooling agent comprising the cooland condensed low boiling liquid overhead products removed from thestabilizer, simultaneously subjecting liquid condensed within thestabilizer to indirect heat exchange with a portion of the vaporsleaving the reaction chamber, the remaining vapors from the reactionchamber being passed to the fractionator, thus heating the liquid withinthe stabilizer and causing the removal therefrom of low boiling andgaseous components,

and stabilizing the remaining liquid, withdrawing to the cracking stepfor retreatment, passing the fractionated vapors to a stabilizing zoneand condensing and stabilizing the gasoline therein, the gasolinecondensate being collected in the lower portion of the stabilizing zoneand withdrawn therefrom as a product of the process, passing the otherportion of the separated vapors in indirect heat exchangewith thegasoline condensate in the lower portion of the stabilizing zone andsubsequently introducing the same to the fractionating zoneforfractionation and subsequent stabilization in adrnixture with thefirst-mentioned portion of the vapors.

6. A process which comprises subjecting hydrocarbon oil to crackingtemperature in a cracking zone'maintained under pressure and separatingthe same therein into vapors and unvaporized oil, passing the separatedvapors to a fractionating zone, flash distilling the unvaporized oil bypressure reduction and introducing the resultant flashed vapors to thefractionating zone for admixture with the rst-mentioned vapors,fractionating the commingled vapors in the fractionating zone tocondense fractions thereof heavier than gasoline and returning resultantreilux to Vthe cracking zone for retreatment, supplying the

